Deposition of coatings onto the interior surface of tubular structures is needed for various applications, including, but not necessarily limited to gun barrels, automotive cylinder bores, and tubes for special applications.
Tubes with relatively large diameters have been successfully coated using known methods. However, as the diameter of the tube becomes smaller and smaller, it becomes more and more difficult to deposit a substantially uniform coating over the entire interior surface. Most methods simply do not succeed if the aspect ratio (length-to-diameter ratio) of the tube is high.
Effective and economical methods are needed to form substantially uniform coatings on interior surfaces of tubes with a high aspect ratio.